Conducting bearing



July 269 B949 c. c. PATTON CONDUCTING BEARING Filed April 4, 1944 INVENTOR. C16. P4770 TTR/Vfy Patented July 206, 1949 coNnUc'riNG BEARING Charles C. Patton, Chicago, Ill., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application April 4, 1944, serial No. 529,516

4 Claims. l

same time provide as frictionless a contact as possible between the elements, the bearing surface of one of the relatively rotatable elements is provided with a gold plating and the other of the bearing surfaces is gold plated on copper, which, in turn, is applied on a base metal and wherein the copper-gold-base metal is heattreated to eiect a partial alloying of the copper and gold, thereby to present a, hard gold surface for engagement with the soft gold surface on the other bearing element.

A complete understanding of the invention may be had by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawing, wherein Fig, 1 is a side elevational View on a greatly enlarged scale, partly in section, of a pair of bearing members mounted in telescoping relation and having bearing surfaces formed in accordy the invention, these two members have been shown as two tubular relatively rotatable elements, designated generally by the numerals 3 and 4. In order to increase the degree of conductivity between the two members 3 and 4, which may comprise bases 5 and 6, respectively, made of bra-ss and steel, the brass surface may be plated with a mtal of high conductivity, such as gold, which is applied thereto in a thin coating 1. The outer surface of the element 6, which is to bear in and be electrically conductive with respect to the element 3, has, in accordance with the present invention, a plating 8 of copper applied thereto by any suitable method, for example, by electroplating it and, thereafter, the copper plate 8 has a plating 9 of gold applied to it to bear against the plating 1 of gold on the brass tube 5. The gold plated surface 1 of the element 3 may be used in the same condition that it attains when it is plated thereon. In other words, the plating l of gold will be relatively soft. However, in order to prevent the plating 9 of gold on the inner element 4 from seizing when the elements 3 and 4 are moved relative one to another, the element 3, with the plating 8 of copper and 9 of gold thereon, is heattreated to effect an interalloying or penetration of copper into the gold and the gold into the copper, thus to harden the outer surface of the gold.

In the preferred embodiment of the invention, the steel tube, after it has been properly machined, may be plated with approximately .005" of copper and upon the copper there may be plated .002 of gold. After the copper and gold in superposed relation have been plated onto the spect to the plain gold-plated brass tube 3, the

bearing surface on the tube or element 4 is quite hard and when the two elements are moved with respect one to another, the friction between them is quite low. The migration or diiusion of the gold into the copper and copper into the gold during the heat treatment sometimes results in the formation of a visible copper scale on the outer surface of the gold, indicating that some of the copper travels completely through the plating of gold. IWhen this occurs, the copper scale lmay be removed by dipping the bearing in a mild solution of nitric acid. In this manner, a friction bearing is provided which has substantially the same conductivity across its bearing surface as would be provided by two soft gold surfaces in engagement with one another, but has none of the tendency of two soft gold surfaces to grab or seize when they are moved with respect to another.

What is claimed is:

1. A frictional bearing comprising a metal foundation having a copper surface, a gold plated coating over the copper surface and lnteralloyed therewith, and a irictionai member having a base metal foundation provided with a gold plated friction surface.

2. In an electrically conductive corrosion resistant low friction bearing, a bearing member having a pure gold bearing surface, and a bearing member having a surface coating in engagement with the pure gold bearing surface, said surface coating being harder than said' pure gold bearing surface and comprising a layer of copper and a layer of gold superposed on said layer of copper and interdliused therewith.

3. In an electrically conductive corrosion resistant low friction bearing, a bearing member having a gold bearing surface, and a 'nearing member comprising a hard base metal, a layer of copper on the base metal, and a layer of gold on and interpenetrated with the layer oi' copper. 20

4. In an electrically conductive corrosion resistant low friction bearing, a bearing member having a pure gold bearing surface, and a bearing member comprising a relatively hard base metal, a layer oi copper plated on said base metal, n

and a layer of gold plated on and partially interalloyed with said layer of copper.

CHARLES C. PATTON.

REFERENCES CITED The following references are of record in tl'ie le of this patent:

UNITED STATES PATENTS Number Name Date 376,900 Morell Jan. 24, 1888 1,800,961 Payne Sept. 21, 1926 1,823,450 Helmond Sept. 15, 1931 2,145,460 Ryder Jan. 3l, 1939 2,203,411 Green June 4, 1940 2,241,789 Queneau May 13, 1941 2,266,320 Hobbs Dec. 16, 1941 2,283,219 McCullough May 19, 1942 2,297,385 Bierdermann Sept. 29, 1942 2,316,119 Bagley Apr. 6, 1943 FOREIGN PATENTS Number Country Date 441,812 Great Britain Jan. 27, 1936 

